HP splits its laser line into Pro and Enterprise. The Pro machines covered here run on what HP internally calls the phx platform — an ARM SoC formatter with firmware in eMMC/NAND and a small I²C EEPROM holding device configuration.
The phx name is not marketing, it comes straight out of the firmware build
strings: assert records inside the NVRAM carry paths like
/work/jenkins/gitbuilder2/workspace/phx@@94cd3ca.